To recreate the same servers into maniaplanet 4, you have to first convert your MP3 maps in MP4.
If you have few maps, you can launch them in the MP4 map editor and then compute shadows and check out if there is no hole and save them.
If you have plenty maps, you can use a tutorial for converting maps from MP3 to MP4: viewtopic.php?p=282170#p282170

A small addition for servers using the dedimania world record database.
You can use your dedimania codes from MP3 for your MP4 servers as well.We are currently doing so under PyPlanet and it works without any problems.

Don't panic. The first page is related to your MP3 account and the latter is MP4 account. At the moment of the update, all the accounts from MP3 were imported into the MP4 database. But after that, the two accounts are dissociated. So if you changed your MP3 password, it won't work on MP4. Nevertheless, the IG account is related to MP4. So all you have to do (since the "forgot password" button is not working on the MP4 page at the moment) is to reset your password from the game. To do this, when launching the game, before pressing "connection", just choose "use other profile", then "create profile", then "login" and then "I forgot my password".

A small addition for servers using the dedimania world record database.
You can use your dedimania codes from MP3 for your MP4 servers as well.We are currently doing so under PyPlanet and it works without any problems.

A small addition for servers using the dedimania world record database.

Small addition to the addition: the Dedimania server (dedimania.net) currently has hardware problems and a ticket has been filed to its data center. Any Dedimania errors in your controller should be ignored for the time being.

Edit on 2017-05-12: The entire Dedimania set-up will have to be rebuild on new hardware and Slig is currently strained for time, so it's likely to take a number of days before full service is restored.

For those with large/very large serverlists: I made a small bash script which might help you "importing" your gameserver accounts into mp4.
It basically signs you in the mp3 playerpage, downloads a list of your gameservers, signs you in into the current playerpage and creates server by server.

It does not import the correct password, it does not import the current zone.
You can set the zone in which they should be located inside the bash script as well as a common password which should be used for all servers. Anyway, you could also choose to generate a password for each server automatically by leaving the default_serverpassword variable empty (which I recommend).

As the comment states, you could also just leave it and invoke the script later on with your username and password as arguments, but this might leak your credentials to some logging mechanism, so you are strongly advised not to do so and instead change it inside the script. For example:

This will "import" the serveraccounts into mp4 and will create a CSV spreadsheet which contains tuples of serverlogin-password, which is especially useful when letting the script generate passwords for each server.

You also get an output to the command line displaying the current progress:

Attention: This script is most likely erroneous, will produce errors, and might not import all of your servers. Just check the results twice and don't blame me

And yes, this requires some kind of unix/linux environment providing a bash (but well, at least Windows has something called Bash on Ubuntu on Windows which might work as well). Also you will need a tool called wget.

I can not login at maniaplanet.com with my account. It says invalid login or password. I can not create a new one because I dont know where to do so on this page and I can not recover my password because the "Forgot Password?" button does nothing.
I just want to register my server into the MP4 account manager.
May someone help me please?

I did the above. (For Ladder servers, you have to formalize them again)
40k planets is now taken from my account.
I have paid once (in MP3) for this server!!!
Bad bad bad!

I wanted to ask this as well. I did not touch my mp3 dedi config on the previous playerpage and now -40k from my account again. How should this be sorted out? Can we get back our previous desposit somehow? Should we delete our login on the older playerpage?